Hi Abhijeet,
Thanks for using Syncfusion Products.
You can achieve your requirements using dockingManager1_DockVisibilityChanged Event, and Treeview_Leave events in your application.
Plaese refer the attached sample.
http://websamples.syncfusion.com/samples/Tools.Windows/F63899/main.htmPlease let me know if this helps.
Thanks and Regards,
Rashidha.